function _burn(address sender, uint256 tBurn) public {
            
        uint256 rBurn = tBurn.mul(_getRate());

        _tTotal = _tTotal.sub(tBurn);
        _rTotal = _rTotal.sub(rBurn);

        _rOwned[sender] = _rOwned[sender].sub(rBurn);
        if (_isExcluded[sender])
             _tOwned[sender] = _tOwned[sender].sub(tBurn);

        address burnAddress = address(0);
        _rOwned[burnAddress] = _rOwned[burnAddress].add(rBurn);
        if (_isExcluded[burnAddress])
            _tOwned[burnAddress] = _tOwned[burnAddress].add(tBurn);    

        emit Transfer(sender, burnAddress, tBurn);
    }